Pneumatic tool.



G. H. GILMAN.

PNEUMATIC TOOL. APPLlcrmu men Amm. :90s.

.K xl. Ain.. l

f .lllll GEORGE H. GILMAN, F CLAREMONT,

MENTS, TO SULLIVAN MACHINERY PORATION OF MASSACHUSETTS.

NEW HAMPSHIRE, ASSIGNOR, BY MESNE ASSIGN- COIVIPANY, 0F BOSTON, MASSACHUSETTS, A. COR- PN EUMATIC TOOL.

Specification of Letters Patent. VPat(51m-139111(Aug. 14, 191'?.

Application led April 22, 1908. Serial No. 428,618.

. To all 'whom t may concern.'

' like letters on the drawings representing like taken in connection with ment with the hollow casing parts.

My invention relates to pressure-Huid tools adapted to be operated by compressed air or other elastic pressure fluid, being more particularly concerned with the provision of simplified. and eflicient valve-controlling means therefor.

My invention will be best understood by reference to the following description when the accompanying illustration of one specic embodiment thereof, while its scope will be m re particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a longitudinal, central section taken through a pneumatic hammer embodying one form of my invention and Fig. 2 is a similar sectional view taken in a plane at right-angles to the plane of the section shown in Fig. 1. l

Referring to the drawings and to the embodiment of the invention. shown therein, there is provided a cylinder 1, the rear or upper end of which has threaded engage- 2, the latter having a closed end and acting as a housing for the rear end of the cylinder and for the valve block 3. The cylinder is prevented from accidental unscrewing by the split clamping collar 4. A portion of the handle no vvpiece or other member by which the tool is supported is shown, but it will be understood that the particular construction of handle forms no material part of this invention and that the same may be used with various forms of handles or well known in the art.

The upper end of the cylinder chamber is closed by the forward wall of the valve block 3, there being provided a valve block plate or cap between the upper end of the valve block and the walls of the casing 2. The cylinder, valve block and plate are I same direction with the piston,

other supports .l

maintained in the alinement required for the registration'of connecting passages by means of a dowel pin 7. The head of the casing is recessed at 8 to provide a constant pressure supply chamber to which, when the tool is in use, compressed air or other pressure fluid is constantly-supplied through the air inlet 9.

The valve block is of a generally cylindrical shape and has an interiorly formed valve chamber axially alined with the cylinder.

The illustrated form of valve instead of moving in a direction opposite to the direction of the piston is arranged to move in the that is to say, it is arranged to move consequent upon the piston movement and in the same direction as the piston. For this purpose the enlarged hea'd 10 of the valve works in an enlarged chamber portion 11 located at the rear of the valve block and connected with the intermittent pressure passage 12 of the cylinder by the passage 13. The forward or contracted portion of the valve chamber is constantly opened to lateral passage 14 and longitudinal passage 15, the latter communicating at the upper face of the plate 6 with the constant pressure chamber 8.

The contracted portion ofthe valve chamber is provided with two annular chamber grooves 16 and 17, both of which are in constant communication with the rear end of the cylinder (Fig. 2) through the medium of the longitudinal passage 18. In the rearmost position of the valve (Fig. 2) the forward end of the valve chamber 1s opened to the groove 16 and the cylinder `ports 18 admitting pressure fluid thereto through the uncovering of the groove `16 by the end face of the reduced or contracted head portion 19 of the valve. In this position pressure fluid is therefore freely admitted to the rear end of the cylinder. Pressure fluid is admitted to, and exhausted from, the forward end of the cylinder through a passage 20 opening into thecylinder through the` port 21, the latter being located near the forward end of the cylinder. The passage 20 extends longitudinally the walls of the cylinder and the valve block and communicates with the enlarged rearward portion of the valve pressure fluid through the chamber through the passage 22. In the rearward position of the valve the passage 22 and therefore the forward end of the cylinder is opened to the exhaust through the annular valve groove 23, which latterplaces the passage 22 in communication with the exhaust port or ports 24, the latter maintaining constant communication between the enlarged valve chamber and the annular exhaust space 25, which is located between the valve lock and the housing or casing 2. The latter is perforated at one or more points such as 26 and 27 so as to permit free exhaust of'pressure fluid tothe atmosphere through the port or ports 24.

The piston has the reduced portion 27 hav-l ing a sliding fit within the contracted walls 28 of the cylinder, the effective area against which Athe pressure acts in returning the piston being that provided by the shoulder formed between the contracted portion and the main body portion of the piston. Y

When the yreturn piston movement has proceeded far enough to withdraw the' reduced piston portion 27 from the contracted cylinder walls 28, the forward end of the cylinder is placed in communication with the tool space 29, the latter 4heing in free communication with the atmosphere through the exhaust opening 30.

At theend of the forward stroke the hammer iston delivers, its blow upon the shank of t e tool 31, the latter held within the usual sleeve or bushing 32. Durin the forward movement ofthe piston the va ve is held in the position shown in Fig. 2 by the pressure acting against the smaller constant pressure area at the forward end of the valve. Near the close of the forward movement of the piston the controlling -valve is reversed by the adm ission of pressureiiuid to the larger area at -'the rear of the [valve v and in the enlarged portion .of the valve chamber which liuid acting. against the larger pressure area thereat reverses the valve against the constant pressure upon the Vmeans of a circumferential groove 34 formed forward end. Pressure fluid is admitted to the'enlarged rear end of the valve chamber through the intermittent pressure passage 12, which latter is placed in communication with the constant pressure passage 33 by in the piston. The passage 33 opens into the cylinder through the ort 35 and is adapted to beconnected with t e port 36 opening into the passage 12. When the circumferential groove uncovers the ports 35 and 36 pressure fluid is admitted to the upper .part of the chamber to move the valve forward to the position shown in Fig. 1. In this position pressure fluid is cut off from the annu-V lar chamber groove 16 --while the` 'annular groove 17 is opened to the forward end of the enlarged valve eliamber portion so that pressure fluid exhausted, 'from .the rear be brought into registration with-the lateral;-

passage 22 when the valve is advanced to .the-

position shown-in Fig; 1. In this osition of the valve therefore pressure flui is adf miti-.ed tothe forward end of the c linderto return the piston thiou h the ho low interior of the valve, the ra ial ports v3,7, groove 38, passage 22 and return paage 20.

Theconstant pressure passage 33 opening intothe cylinder is in constant communication with the live pressure passage 15 as shown in Fig. 1.

It will be-evident that on the rearward.

stroke of the piston the valve is again moved from the position shown in Fig( l to. that.

shownin Fig. 2 when the secolivd otvlin'ore advanced port 39 connected witlim-th"inter-.I

mittentV pressure passage 12 is uncovered'by the piston and opened tothe exhaust passage, 30, v:this resulting in exhausting4 the pressure fluid from the larger-area'at-- thel rear of the valve chamber and causin the pressure' Huid at the forward end o the valve to lift the same to the position' shown in Fig. 2. j

While I have hereinshown and described in detail for purposes of illustrationone spe cilic embodiment; of the invention, itis to be understood thatsthe# me is not limited to the'details showni or` o the construction or lrelative arrangement of parts disclosed, but

that extensive modifications may be made.

therein without departing from the spirit of the invention- What Iclaim and desire to secure by Letters Patent is:

1.. pressure fluid zorg havilg a cylinder, a piso @arpresfsure ui supp assa e --a hollow DXvallve;provided` with tvlfropheadgs ,of diiferent Idiameter separated by an exterior annular groove, the end of the smaller head being open and having about its opening an l annular surface constantly exposedto pres" sure fluid fromsaid pressure Huid supply passage, and the end of the larger head belng closed to the entrance of pressure-duid a port connected w'ith the rear end of said cylinder and extending' across said annular surface of the smaller head into direct communir/ation with said pressure fluid supply passage, the smaller head being adapted to alternately open and close suoli communism non across said annular'surfnes. a vert son:

nected to the forward end of the cylinder and adapted to be intermittently opened to the hollow interior ofthe valve, and an exhaust passage communicating with the space about the annular groove of the valve and adapted to be placed alternately in communication with the opposite ends of the cylinmunication with said der.

2. A pressure fluid toolhaving a cylinder, a piston, a pressure fluid supply space, a hollow valve located at the rear of the cylinder and in alinement therewith, said valve being provided,.with two heads of different diameter Separated by an exterior annular groove, the end 'of the smaller head being open and having about its opening an annular surface constantly exposed to pressure fluid from said pressure fluid supply passage, and the end of the larger head being closed to the entrance of pressure fluid, a port connected with the rear end of said cylinder and extending across said annular surface of the smaller head into vdirect compressure fluid supply passage, the smaller head'ibeing adapt/ed to alternately open and close such.' communication across said annular surface,..-a port connected to the forward end of this cylinder andy adapted to be intermittently opened to the hollow interior of the valve, and an exhaust passage communicating with the space about the annular groove of the valve and adapted to be placed alternately in communication with the opposite ends of the cylinder.

3. A pressure iuid tool having a cylinder, a piston, a pressure iiuid supply passage, a hollow valve provided with. two heads of different diameter and. having an exterior annular groove,-the smaller head being imperforate and the larger head being perforated by one or more lateral passages opening outward from the hollow interior of the valve, thel end of the smaller head being open and having about its opening an annular 'surface constantly exposed to pressure fluid from said pressure fluid supply passage, and the end of the larger head being closed to the entrance of pressure fluid, a port connected with the rear end of said cylinder and extending across said annular surface of the smaller head .in direct communication with said pressure Huid supply passage, the smaller head being adapted to alternately open and close said communication across said annular surface, a port connected to the forward end of the cylinder and adapted to be intermittently opened to `the hollow interior of the valve through communication with said lateral valve passage or passages, and an exhaust passage communlcatlng with the space about the an- Gopies of this patent may be obtained for ve cents each, by Washington, D. C.

nular groove of the valve adapted tol be placed alternately in communication with .annular groove, they smaller head being pro vided with an annular surface constantly exposed to pressure fluid from said pressure fluid supply passage and having means for admitting pressure fluid to the interior of the'valve, and the end of the larger head being closed to the entrance of pressure fluid, a port connected with the rear end of said cylinder and extending across saidl annular surface of the smaller head into direct communication with said pressure fluid supply passage, the smaller head being adapted to alternately open and close such communication across said annular surface, a port .connected to the forward end of the cylinder and adapted to be placed intermittently in communication with the interior of the valve and the pressure fluid supplied therethrough from said pressure fluid supply passage, and an exhaust passage communicating with the space. about the annular groove of the valve and adapted to be placed alternately in communication with the opposite endsl of the cylinder.

5. A pressure Huid tool having a cylinder, a piston, a pressure fluid supply passage, a hollow valve provided with two heads of different diameter separated by an exterior annular groove, the smaller head at the forward end of the valve being open and constantly exposed to the pressure fluid supply in said pressure fluid supply passage, and the end of the larger head being at the rear and closed and exposed to intermittent pressure, a port connected with the rear end ofthe cylinder and vextending across the end face of the smaller head of the valve into direct communication with said pressure fluid passage, the smaller head of the valve being GEORGE H. GILMAN. Witnesses E; J. BRUCHARD, J. A. BRUCE.

addressing the Commissioner of'- Ratents.

Correction in Letters Patient No. 1,236,701.

` It ie hereby certified that in Letters Patent No. 1,236,701, granted August 14,

1917, upon the application of George H. Gilman, of Claremont, New Hampshire,

. forA an improvement in Pneumatic Tools, an error appears in the printed speciication requiring correction as follows:A Page 3, line 107, claim-5, after'the Word fluid insert the word supply; and that the saidlLletters Patent should be read Y with this correetion therein that the same may conform to the record of the case in the Patent Office.'

Signed and sealed thie 25th .day of September,'A. D., 1917.

['mn] p y F; W.` H. CLAY, 

